Function CFRunLoopObserverCreateWithHandler 

pub unsafe extern "C-unwind" fn CFRunLoopObserverCreateWithHandler(
    allocator: Option<&CFAllocator>,
    activities: CFOptionFlags,
    repeats: bool,
    order: CFIndex,
    block: Option<&DynBlock<dyn Fn(*mut CFRunLoopObserver, CFRunLoopActivity)>>,
) -> Option<CFRetained<CFRunLoopObserver>>

👎Deprecated: renamed to CFRunLoopObserver::with_handler

Available on crate features CFRunLoop and block2 only.